This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Chemical Bonding 4 IONIC, METALLIC & COORDINATE BONDS University of Lincoln presentation

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Ionic Bonding

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License IONIC BONDING Very important form of bonding – main bonding mechanism of metals: >80 elements are METALS 19 elements are non-metals 5 elements are metalloids

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Ionic Bonding – main bonding mechanism of the metals Ionic

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Forming Ionic Bonds IONIC BONDS are electrostatic in nature, and are formed by transferring electrons from an electron giver to an electron taker ELECTRON GIVERELECTRON TAKER e–e– Cation (+) Anion (-)

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Electron Givers Most metals have 1–3 valence electrons that they would like to lose Metals are therefore ELECTRON GIVERS

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Electron Takers Elements on the RHS of the periodic table (non-metals) would like to gain electrons Non-metals are therefore good ELECTRON TAKERS

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License For Example… Cu(I)Cu – e –  Cu + Cu(II)Cu – 2e –  Cu 2+ O + 2e –  O 2– Overall reactions: Cu(I)4Cu + O 2  2Cu 2 O Cu(II)2Cu + O 2  2CuO

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Some Common Ions ANIONS SymbolName Cl – Chloride O 2– Oxide O 2 2– Peroxide S 2– Sulphide CO 3 2– Carbonate SO 4 2– Sulphate OH – Hydroxide SiO 4 4– Silicate CATIONS SymbolName Na + Sodium K+K+ Potassium Ca 2+ Calcium Cu + Copper(I) Cu 2+ Copper(II) Fe 2+ Iron(II) Fe 3+ Iron(III) Sn 2+ Tin(II)

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Structural types Common geometries adopted: Octahedral geometry Tetrahedral geometry

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License There are only a few structural shapes adopted in solid ionic compounds (salts): Rock Salt (sodium chloride) Caesium chloride Fluorite (calcium fluoride) Rutile (titanium(IV) oxide) Structural shapes

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Rock Salt Structure CompoundFormulaCationAnion Sodium chlorideNaClNa + Cl – Sodium fluorideNaFNa + F–F– Sodium hydrideNaHNa + H–H– Lithium chlorideLiClLi + Cl – Potassium bromideKBrK+K+ Br – Potassium iodideKIK+K+ I–I– Silver fluorideAgFAg + F–F– Silver chlorideAgClAg + Cl – Magnesium oxideMgOMg 2+ O 2– Calcium oxideCaOCa 2+ O 2– Barium oxideBaOBa 2+ O 2– Iron(II) oxideFeOFe 2+ O 2– Magnesium sulfideMgSMg 2+ S 2– Lead(II) sulfidePbSPb 2+ S 2–

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Rock Salt Type – cubic Cation + Anion – The COORDINATION NUMBER of each Cation + ion = 6 The COORDINATION NUMBER of each Anion – ion = 6 NaCl: 801 C S=35.9g/100ml (25C)

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License The COORDINATION NUMBER of an ion is the number of nearest neighbours Definition…

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Caesium Chloride Type – BCC BCC = Body centred cubic Cesium chloride unit cell (space filling diagram) Cesium chloride unit cell (ball and stick diagram)

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Caesium Chloride Type – BCC Cation + Anion – The COORDINATION NUMBER of each Cation + ion = 8 The COORDINATION NUMBER of each Anion – ion = 8 CsCl: 645 C S=162g/100ml (1 C) A unit cell of caesium chlorideExtending the caesium chloride structure

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Fluorite Type Cation + Anion – The COORDINATION NUMBER of each Cation + ion = 8 The COORDINATION NUMBER of each Anion – ion = 4 CaF 2 : 1402 C S=virtually insoluble CaF 2 unit cell

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Rutile Type Cation + Anion – The COORDINATION NUMBER of each Cation + ion = 6 The COORDINATION NUMBER of each Anion – ion = 3 TiO 2 : 1870 C S=Insoluble Unit cell of rutile type TiO 2

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Metallic Bonding

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Solid State Metals METALLIC BONDING is a variation on both covalent and ionic bonding: The bonding is electrostatic in nature (like ionic) but involves the sharing of electrons (like covalent) over many atoms of the same type

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License The Metallic Bond Metal ion Electron The structure of a metal consists of a lattice of bonded metal cations with a ‘sea of electrons’. The electrons are not bound, and can move throughout the structure – hence metals are good conductors of electricity

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Coordinate Bonding

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Transition Metals The TRANSITION METALS (d- and f-block metals) usually form COORDINATE BONDS

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License The Coordinate Bond The COORDINATE BOND occurs when a species donates its lone pair of electrons to a metal ion Cl Lone pair The metal does NOT use its own valence electrons for bonding Fe 2+

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Definition… A species that donates a lone pair of electrons to a metal ion to form a coordinate bond is called a LIGAND A ligand can be either anionic or neutral

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Definitions… oCovalent bond oIonic bond oMetallic bond oCoordinate bond oCoordination number oLigand

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License Acknowledgements JISC HEA Centre for Educational Research and Development School of natural and applied sciences School of Journalism SirenFM